1. Field of the Invention
The present invention relates to an epoxy resin composition suitable for use as a semiconductor encapsulating material, which displays excellent resistance to high temperature, flame retardancy and moisture resistance, and moreover does not use conventional flame retardants such as antimony compounds and halogenated epoxy resins.
2. Description of the Prior Art
In the field of semiconductor devices, resin encapsulated devices such as diodes, transistors, ICs, LSIs and ultra LSIs are common, and because epoxy resins offer superior levels of moldability, adhesion, electrical characteristics, mechanical characteristics and moisture resistance when compared with other thermosetting resins, the encapsulating of semiconductor devices with epoxy resin compositions is widespread.
Conventionally, in order to ensure that such epoxy resin compositions meet the UL-94 V-0 flame retardancy specifications, a brominated epoxy resin and antimony trioxide are typically combined and added to the composition as flame retardants. This combination of a brominated epoxy resin and antimony trioxide provides a gas phase radical trap and a powerful air blocking effect, and as a result, produces a strong flame retardancy effect.
However, brominated epoxy resins generate toxic gas on combustion, and antimony trioxide also has an associated powder toxicity, and consequently if the effect on both people and the environment is considered, then naturally it is desirable that a resin composition comprises neither of these flame retardants.
With this in mind, the use of hydroxides such as Al(OH)3 and Mg(OH)2, and phosphorus based flame retardants such as red phosphorus instead of brominated epoxy resins or antimony trioxide is currently being investigated. However, when any of the proposed compounds is actually used, a variety of problems arise such as a deterioration in curability during molding, or a deterioration in moisture resistance, and none of the proposed compounds has been able to satisfy the levels of reliability required for semiconductor devices, meaning that at present, no compounds are put into practice.